The present invention pertains to torque controls, and in particular to a torque control specially suited for providing a desired frictional resistance to a pivotally mounted armrest, headrest or other articulated vehicle accessory.
Many vehicular components, as well as elements in other fields, are mounted for selective controlled pivotal movement. Often it is desirous to frictionally attach the component to provide either a controlled movement between set positions or an adjustment capacity which permits the user to adjustably position the component at specific locations. Previously, frictional forces have generally been provided by a relatively tight frictional engagement between opposing washers or the like, along the pivot pin, axle, etc. Further, provision of adjustment capabilities has often been provided by a mechanical, spring biased detent structure. However, all of these arrangements require the manufacture and assembly of a multiple of parts which, in turn, causes an increase in fabrication costs. Also, with extended use these systems tend to loosen and wear, which thereby decreases their effectiveness and may cause rattling of the joint parts.
In an effort to alleviate the shortcomings of the previous systems, torque controls including resilient plastic tubular members which are stretched or distorted by a rotating cam-like axle have been developed. An example of such a device is illustrated in U.S. Pat. No. 4,734,955 issued Apr. 5, 1988 to Connor, and entitled HINGE MECHANISM FOR A VEHICLE VISOR. However, these systems require the specific irregular shaping of both connector elements (i.e., the shaft and socket elements) which create additional manufacturing costs. Also, the amount of resistance which may be offered is limited, due to the small moments engendered by providing the frictional resistance almost coincident with the rotational axis.